1. Field of the Invention
The present invention relates to a distributor for use with internal combustion engines of automobiles etc., and more particularly to a distributor for internal combustion engines which includes a plurality of connectors for electrically coupling the interior and the exterior of the distributor, and a rotation signal detector.
2. Description of the Related Art
In internal combustion engines of automobiles etc., generally, a low-voltage current introduced from a battery is converted by an ignition coil into a high-voltage current which is then supplied to a distributor. In the distributor, the high-voltage current is supplied by a distributing rotor to cylinder's spark plugs in sequence so that a spark is emitted to set off ignition in each of the cylinders.
Of late, there is a tendency to arrange parts necessary for ignition inside a distributor collectively from the standpoints of creating a space in the engine room and reducing the cost. An ignition coil for generating a high-voltage current, for example, is arranged inside the distributor. In this case, the following arrangements are proposed with a view of meeting demands from automobile manufacturers and users.
(1) Ignition Coil at Top of Distributor
As disclosed in JP, A, 63-75356, for example, a shaft rotating synchronously with an engine is vertically disposed, and an ignition coil is disposed on an extension of the shaft axis and at the top of a distributor. Further, a signal rotor rotatable with the shaft and a rotation signal detector of magnetism detecting type located to face the signal rotor are disposed in a lower portion of the distributor.
(2) Ignition Coil in Lower Portion of Distributor
As disclosed in JP, U, 4-59371, for example, an ignition coil is disposed in a lower portion of a distributor while a vertical shaft is penetrating the ignition coil. On the other hand, a signal rotor and a rotation signal detector of light detecting type are disposed in an upper portion of the distributor. Thus, the rotation signal detector and the ignition coil are arranged in a vertically two-layered structure.
(3) Rotation Signal Detector and Ignition Coil on Both Sides of Shaft
As disclosed in JP, A, 4-203358 and JP, A, 4-27724, for example, a signal rotor and a rotation signal detector of light detecting type are disposed nearly at the center of a distributor. The rotation signal detector and the ignition coil are disposed in opposite sides with a shaft therebetween.
The distributor of above (3) type has a connector for electrically coupling the interior and the exterior of the distributor. More specifically, as the signal rotor is rotated, the crank angle position of an engine is detected as an interrupted signal (hereinafter referred to as crank angle position signal) by the rotation signal detector, and the crank angle position signal is transmitted to an engine control unit through the connector. Upon receiving the crank angle position signal, the engine control unit outputs an ignition timing signal for the engine, which is introduced back to the distributor through the connector and then transmitted to the ignition coil through a lead.
At the same time, source power is supplied from the engine control unit to the ignition coil through electrical connection separately established from that made by the above connector. Such separate electrical connection is obtained by, e.g., connecting the engine control unit and the ignition coil directly through a lead as disclosed in JP, A, 4-203358. For further improved convenience in handling of parts, however, it is thought to provide another connector (hereinafter referred to also as second connector) for electrically coupling the ignition coil and the engine control unit separately from the above-mentioned connector (hereinafter referred to also as first connector) for electrically coupling the rotation signal detector and the engine control unit, as with the distributor of separate type (above (2) type) disclosed in JP, U, 4-59371. In this case, the ignition coil induces a high voltage at its output terminal from the source power supplied through the second connector in accordance with the timing that is determined by the ignition timing signal transmitted through the first connector.
In the distributor arranged described above, the first connector for electrically coupling the rotation signal detector and the engine control unit is structurally integral with the rotation signal detector. But the second connector for electrically coupling the ignition coil and the engine control unit is positioned near the ignition coil, i.e., on the side opposite to the rotation signal detector, and is structurally separate from the first connector and the rotation signal detector. In other words, because the first and second connectors are disposed in spaced opposite relation, the distributor must be turned upside down during assembly after attaching one of the connectors, in order to attach the other. This is disadvantageous from the viewpoint of working efficiency. Another disadvantage is that the number of steps is increased, which leads to a difficulty in achieving high productivity. Further, in the present situations where ignition parts are collectively disposed inside a distributor and the density of parts in the distributor is overly increased as described before, wire distribution from the separate connectors is unhandy to perform, which also impedes an improvement in working efficiency and productivity. Additionally, inconvenience in handling of parts is also suffered during maintenance for the same reason.